The soluble urokinase plasminogen activator receptor and its fragments in venous ulcers

Methods for sampling wound fluid from venous leg ulcers for molecular analyses: A scoping review

Determining the precise role of molecular factors present in venous leg ulcer exudate will expedite the identification of biomarkers that can optimally guide treatment. However, there is now no standardized approach for collecting, processing and storing wound fluid samples for molecular analyses. This scoping review was conducted to integrate and summarize the multiple types of methods being used currently in studies of venous leg ulcers for collecting, processing and storing wound fluid prior to analysis. PubMed, CINAHL, EMBASE and Scopus databases were searched for eligible studies between 2012 and 2022. Nineteen studies were selected for this scoping review. Five primary methodological categories for wound fluid sampling were identified. The most commonly used collection method involved extracting the fluid from various absorbent materials, and the majority of studies centrifuged wound fluid before storing it at ultra-low temperatures. This review found the wound fluid sampling methods among the included studies to be heterogeneous. Moreover, the data revealed no definitive patterns. There is a critical need to develop standardized wound fluid sampling methods in research to facilitate accurate comparisons of biomarker data across studies and a more rapid determination of biomarkers that can most effectively guide delivery of tailored venous leg ulcer treatments.

The association of wound factors and symptoms of fatigue and pain with wound healing in chronic venous leg ulcers

The purpose of this study was: (1) to characterise the association of wound area, wound exudate C-reactive protein (CRP), broad-spectrum matrix metalloprotease protein (MMPs), and symptoms of fatigue and pain in individuals with chronic venous leg ulcers (CVLUs) over time and (2) to identify factors associated with the wound healing trajectory in CVLUs. Seventy four participants with CVLU who received weekly sharp debridement were recruited from a wound care clinic during the 8-week study period. To examine associations among wound CRP, MMPs, pain, fatigue, and wound healing trajectory over time, we calculated Bayes factors (BF) based on a linear mixed model. The mean age of participants was 71.8 (SD = 9.8) and the mean wound area was 2278 mm² (SD = 7085 mm² ) at baseline. Higher fatigue was strongly associated with higher MMPs (BF = 9, 95% HDI: [-.05, .43]), lower CRP (BF = 11, 95% HDI: [-.02, .002]), and large areas of wound (BF = 20, 95% HDI: [-.001, .01]). Higher CRP and MMPs activity in wound exudate and higher fatigue were associated with a larger wound area. To facilitate wound healing, clinicians need to utilise the multifactorial approach, which includes wound treatment and management of symptoms such as pain and fatigue, because of the molecular and psycho-behavioural factors involved in wound healing.

Wound fluid sampling methods for proteomic studies: A scoping review

Understanding why some wounds are hard to heal is important for improving care and developing more effective treatments. The method of sample collection used is an integral step in the research process and thus may affect the results obtained. The primary objective of this study was to summarise and map the methods currently used to sample wound fluid for protein profiling and analysis. Eligible studies were those that used a sampling method to collect wound fluid from any human wound for analysis of proteins. A search for eligible studies was performed using MEDLINE, Embase and CINAHL Plus in May 2020. All references were screened for eligibility by one reviewer, followed by discussion and consensus with a second reviewer. Quantitative data were mapped and visualised using appropriate software and summarised via a narrative summary. After screening, 280 studies were included in this review. The most commonly used group of wound fluid collection methods were vacuum, drainage or use of other external devices, with surgical wounds being the most common sample source. Other frequently used collection methods were extraction from absorbent materials, collection beneath an occlusive dressing and direct collection of wound fluid. This scoping review highlights the variety of methods used for wound fluid collection. Many studies had small sample sizes and short sample collection periods; these weaknesses have hampered the discovery and validation of novel biomarkers. Future research should aim to assess the reproducibility and feasibility of sampling and analytical methods for use in larger longitudinal studies.

Protease activity as a prognostic factor for wound healing in venous leg ulcers

BACKGROUND

Venous leg ulcers (VLUs) are a common type of complex wound that have a negative impact on people's lives and incur high costs for health services and society. It has been suggested that prolonged high levels of protease activity in the later stages of the healing of chronic wounds may be associated with delayed healing. Protease modulating treatments have been developed which seek to modulate protease activity and thereby promote healing in chronic wounds.

OBJECTIVES

To determine whether protease activity is an independent prognostic factor for the healing of venous leg ulcers.

SEARCH METHODS

In February 2018, we searched the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Ovid Embase and CINAHL.

SELECTION CRITERIA

We included prospective and retrospective longitudinal studies with any follow-up period that recruited people with VLUs and investigated whether protease activity in wound fluid was associated with future healing of VLUs. We included randomised controlled trials (RCTs) analysed as cohort studies, provided interventions were taken into account in the analysis, and case-control studies if there were no available cohort studies. We also included prediction model studies provided they reported separately associations of individual prognostic factors (protease activity) with healing. Studies of any type of protease or combination of proteases were eligible, including proteases from bacteria, and the prognostic factor could be examined as a continuous or categorical variable; any cut-off point was permitted. The primary outcomes were time to healing (survival analysis) and the proportion of people with ulcers completely healed; the secondary outcome was change in ulcer size/rate of wound closure. We extracted unadjusted (simple) and adjusted (multivariable) associations between the prognostic factor and healing.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion at each stage, and undertook data extraction, assessment of risk of bias and GRADE assessment. We collected association statistics where available. No study reported adjusted analyses: instead we collected unadjusted results or calculated association measures from raw data. We calculated risk ratios when both outcome and prognostic factor were dichotomous variables. When the prognostic factor was reported as continuous data and healing outcomes were dichotomous, we either performed regression analysis or analysed the impact of healing on protease levels, analysing as the standardised mean difference. When both prognostic factor and outcome were continuous data, we reported correlation coefficients or calculated them from individual participant data.We displayed all results on forest plots to give an overall visual representation. We planned to conduct meta-analyses where this was appropriate, otherwise we summarised narratively.

MAIN RESULTS

We included 19 studies comprising 21 cohorts involving 646 participants. Only 11 studies (13 cohorts, 522 participants) had data available for analysis. Of these, five were prospective cohort studies, four were RCTs and two had a type of case-control design. Follow-up time ranged from four to 36 weeks. Studies covered 10 different matrix metalloproteases (MMPs) and two serine proteases (human neutrophil elastase and urokinase-type plasminogen activators). Two studies recorded complete healing as an outcome; other studies recorded partial healing measures. There was clinical and methodological heterogeneity across studies; for example, in the definition of healing, the type of protease and its measurement, the distribution of active and bound protease species, the types of treatment and the reporting of results. Therefore, meta-analysis was not performed. No study had conducted multivariable analyses and all included evidence was of very low certainty because of the lack of adjustment for confounders, the high risk of bias for all studies except one, imprecision around the measures of association and inconsistency in the direction of association. Collectively the research indicated complete uncertainty as to the association between protease activity and VLU healing.

AUTHORS' CONCLUSIONS

This review identified very low validity evidence regarding any association between protease activity and VLU healing and there is complete uncertainty regarding the relationship. The review offers information for both future research and systematic review methodology.

The Influence of AGEs Environment on Proliferation, Apoptosis, Homeostasis, and Endothelial Cell Differentiation of Human Adipose Stem Cells

The aim of this study was to evaluate the changes of proliferation, apoptosis, homeostasis, and differentiation of human adipose-derived stem cells (hASCs) in the simulated diabetic microenvironment and discuss the potential of the mesenchymal stem cell in the treatment of chronic diabetic wound. We simulated diabetic microenvironment with glycation end products (AGEs) in vitro and studied the changes of hASCs in proliferation and apoptosis. We found that AGEs inhibited the proliferation and lead to hASCs apoptosis, and the endothelial cell directed differentiation was also inhibited. AGEs upregulated growth-related oncogene and monocyte chemoattractant protein-1 and downregulated urokinase-type plasminogen activator receptor, which may inhibit the proliferation and transference of endothelial cells. The simulated diabetic microenvironment affects the proliferation, apoptosis, and homeostasis of hASCs, the endothelial cell migration, and the synthesis of collagen protein, leading to delayed wound healing.